Re: [PATCH for 7.2?] target/i386: Remove compilation errors when -Werror=maybe-uninitialized

[Stefan Hajnoczi]

On Wed, 7 Dec 2022 at 09:34, Eric Auger <eric.auger@redhat.com> wrote:
>
> Hi Stefan,
>
> On 12/7/22 15:09, Stefan Hajnoczi wrote:
> > On Wed, 7 Dec 2022 at 08:31, Eric Auger <eric.auger@redhat.com> wrote:
> >> On 12/7/22 14:24, Eric Auger wrote:
> >>> Initialize r0-3 to avoid compilation errors when
> >>> -Werror=maybe-uninitialized is used
> >>>
> >>> ../target/i386/ops_sse.h: In function ‘helper_vpermdq_ymm’:
> >>> ../target/i386/ops_sse.h:2495:13: error: ‘r3’ may be used uninitialized 
> >>> in this function [-Werror=maybe-uninitialized]
> >>>  2495 |     d->Q(3) = r3;
> >>>       |     ~~~~~~~~^~~~
> >>> ../target/i386/ops_sse.h:2494:13: error: ‘r2’ may be used uninitialized 
> >>> in this function [-Werror=maybe-uninitialized]
> >>>  2494 |     d->Q(2) = r2;
> >>>       |     ~~~~~~~~^~~~
> >>> ../target/i386/ops_sse.h:2493:13: error: ‘r1’ may be used uninitialized 
> >>> in this function [-Werror=maybe-uninitialized]
> >>>  2493 |     d->Q(1) = r1;
> >>>       |     ~~~~~~~~^~~~
> >>> ../target/i386/ops_sse.h:2492:13: error: ‘r0’ may be used uninitialized 
> >>> in this function [-Werror=maybe-uninitialized]
> >>>  2492 |     d->Q(0) = r0;
> >>>       |     ~~~~~~~~^~~~
> >>>
> >>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> >>> Fixes: 790684776861 ("target/i386: reimplement 0x0f 0x3a, add AVX")
> >>>
> >>> ---
> >>>
> >>> Am I the only one getting this? Or anything wrong in my setup.
> >> With Stefan's correct address. Forgive me for the noise.
> > When is -Wmaybe-uninitialized used? QEMU's build system doesn't set
> > it. Unless it's automatically set by meson this must be a manual
> > --extra-cflags= option you set.
>
> I am using this configure cmd line:
>
> ./configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib/qemu
> --target-list=x86_64-softmmu --docdir=/usr/share/doc/qemu --enable-kvm
> --extra-cflags=-O --enable-trace-backends=log --python=/usr/bin/python3
> --extra-cflags=-Wall --extra-cflags=-Wundef
> --extra-cflags=-Wwrite-strings --extra-cflags=-Wmissing-prototypes
> --extra-cflags=-fno-strict-aliasing --extra-cflags=-fno-common
> --extra-cflags=-Werror=type-limits
> >
> > If you added it manually then let's fix this in 8.0 since it's not
> > tested/supported and very few people will see this issue.

Did you create the ./configure command-line manually? Do you think
other people will hit this?

Stefan